The attackers appear to be gathering broad intelligence about visitors to three websites, FireEye says

Abobe planned to release an emergency update for Flash Player on Thursday, after security vendor FireEye pointed to a zero-day exploit used by attackers to target visitors to websites of three nonprofits, two of which focus on national security and public policy.

The Flash exploit allowed attackers to target users of the websites of the Peterson Institute for International Economics at PIIE.com, the American Research Center in Egypt at ARCE.org and the Smith Richardson Foundation at SFR.org. The exploit can compromise Flash users on Windows XP or those with Windows 7 who have Java 1.6 or an outdated version of Microsoft Office 2007 or 2010 installed, FireEye said.

The attacks came by remote code injection, with visitors to the affected websites redirected to a server hosting the exploit through a hidden iframe, FireEye said. Representatives of the three websites didn't immediately respond to requests for comments on the attacks, but later the Peterson Institute provided a statement saying it was "taking the situation extremely seriously and doing everything we can to ensure the security of our website."

"We believe the group behind this campaign has sufficient resources ... and is committed to their mission of infecting visitors to a particular type of website," the security company said in its release on the exploit. "The threat actors likely sought to infect users to these sites for follow-on data theft, such as information relating to defense and public policy matters."

The attacks, dubbed "Operation GreedyWonk" by FireEye, appear to be focusing on "broad intelligence gathering efforts," Darien Kindlund, threat intelligence manager at FireEye, said via email. "Based on the websites compromised and the typical visitors to those websites, it seems they are currently focused on intel related to foreign and economic policy activities, at this time."

Adobe Thursday released a security bulletin for Flash Player 12.0.0.44 and earlier versions of the software for Windows and Macintosh, and Flash 11.2.202.336 and earlier versions for Linux. One of the patches is likely related to the exploit discovered by FireEye.

Windows users attempting to avoid the attack should consider upgrading from XP to a newer version of the operating system, updating Java, or updating their Office software, Kindlund said. They should also update Flash as soon as a fix is available, he said.

"Even with patching the OS and applications, the attacker could find another way to trigger the Flash vulnerability outside of the browser/apps listed," he said. "As such, the mitigations outlined in the blog are effective at countering the threat at a tactical level, but addressing the Flash vulnerability is still required, as the attacker could change tactics in their next wave of attacks."

Grant Gross covers technology and telecom policy in the U.S. government for The IDG News Service. Follow Grant on Twitter at GrantGross. Grant's email address is grant_gross@idg.com.